A device used to convert a non-electrical quantity into an electrical signal is called :
Transducer
A transducer converts energy from one form to another, and in instrumentation that means turning a physical quantity into an electrical signal — option 3.
The word itself is the definition: from the Latin transducere, to lead across — across a boundary between physical domains.
| Transducer | Converts | Principle |
|---|---|---|
| Thermocouple | Temperature to voltage | Seebeck effect |
| Strain gauge | Strain to resistance | Geometry and piezoresistance |
| LVDT | Displacement to voltage | Mutual inductance |
| Piezoelectric crystal | Force to charge | Piezoelectric effect |
| Photodiode | Light to current | Photogeneration |
Why the other three are excluded — and it is the same reason each time. All of them are electrical-to-electrical devices: a transformer changes a voltage level, an oscillator generates a waveform from a DC supply, and an inverter converts DC to AC. None crosses the boundary between a physical quantity and an electrical one, which is exactly what the question asks for.
A distinction worth making. A sensor is strictly the element that responds to the measurand, while a transducer is the sensor together with whatever converts that response into a usable signal. In everyday use the words are interchangeable, but the difference matters when reading a data sheet: a bare thermistor is a sensor, and a thermistor with its bridge and amplifier packaged together is a transducer with a calibrated output.
Transducers also run the other way. An actuator — a loudspeaker, a solenoid, a motor, a piezoelectric buzzer — converts an electrical signal back into a physical quantity, and is properly an output transducer. Some devices work in both directions: a loudspeaker used in reverse is a microphone, and a piezoelectric crystal both generates a voltage when squeezed and deforms when a voltage is applied, which is why the same element serves as both transmitter and receiver in an ultrasonic system.
Why the conversion to electrical form is worth making at all : electrical signals can be amplified, filtered, transmitted over distance, digitised and recorded, none of which is convenient for a mechanical or thermal quantity in its original form.
Hence, the device is a transducer.
Similar Questions
Which of the following transducers are not linear ?
i. thermistor
ii. thermocouple
iii. IC sensorWhich of the following sensors has excellent linearity ?
The mechanical elements that are used to convert the applied force into a displacement are called :
Match List - I with List - II.
List - I (Transducers) List - II (Typical Applications) (A) Potentiometric device (I) Relative humidity (B) Resistance hygrometer (II) Velocity (C) Dielectric gauge (III) Displacement (D) Moving coil generator (IV) Thickness Choose the correct answer from the options given below :
Which of the following statements are correct
A. Megnetostrictive transducer operation depends on the change of permeability of magnetic material is when strained.
B. Potentiometer is an active transducer.
C. Turbine flow meters are volumetric flow meters
D. Any metal can be thermistor.
E. Thermocouples are used in high accuracy measurements.
Choose the most appropriate answer from the options given below :
Which of the following statements are correct ?
A. Hygrometer measures the value of humidity directly
B. Hygrometer measures the value of humidity indirectly
C. Wien's bridge is used to measure the frequency of the signal
D. Wien's bridge is used to measure the amplitude of the signal
E. Bimetallic strip is a thermal expansion detector.
Choose the most appropriate answer from the options given below :
Match List I with List II
LIST I LIST II A. Stroboscope I. Changes its electrical resistance with temperature B. Bolometer II. Generate thermoelectric emf C. Thermocouple III. Changes pressure to displacement D. Diaphragm IV. For measurement of rotary motion Choose the correct answer from the options given below:
Consider the following statements associated with electrical and electronic transducers
A. Little power is consumed by transducer
B. Mass intertia effects are not minimized
C. The response time is small
D. Transmission and processing the signal for the purpose of measurement are easier.
Choose the correct answer from the options given below:
Incorrect statements regarding measurement are given :
A. Hot wire anemometer is used to measure displacement
B. Hall effect is used to measure current
C. LVDT is used to measure acceleration and gas flow
D. Piezoelectric Transducer is used to measure acceleration
Choose the correct answer from the options given below:
Match List I with List II
LIST I LIST II A. Relative error I. The ability of tde device to give identical O/P when repeated measurements are made witd tde same I/P signal B. Precision II. The ratio of difference between measured value and tde true value to tde true value of tde measurand C. Caliberation III. The smallest increment in measure tdat can be detected witd certainity by tde instrument D. Resolution IV. The process of making adjustments or tde scale so tdat tde instrument reading conform to an accepted standard. Choose the correct answer from the options given below:
Important Questions from Basics of Transducers
_____ converts mechanical displacement into electrical signals.
Which of the following transducers are not linear ?
i. thermistor
ii. thermocouple
iii. IC sensorWhich of the following sensors has excellent linearity ?
The mechanical elements that are used to convert the applied force into a displacement are called :
Match List - I with List - II.
List - I (Transducers) List - II (Typical Applications) (A) Potentiometric device (I) Relative humidity (B) Resistance hygrometer (II) Velocity (C) Dielectric gauge (III) Displacement (D) Moving coil generator (IV) Thickness Choose the correct answer from the options given below :
